TRANSCRIPT

"Main engine start and lift-off of the Delta rocket carrying Opportunity - a chance to explore and unlock the secrets of our neighbouring planet."

Narration: Within the space of a month, four robots were on their way to Mars.

The stakes were high. Two thirds of all previous missions to Mars had failed.

This time there would be drama and discovery in equal measure. And the Red Planet would never be quite the same again...

'Voyage to the Seas of Mars...'

Narration: If there was a single, main objective of all the missions heading to Mars it was to search for evidence of that most essential of earthly ingredients - water.

Richard Smith, reporter: "The rationale was a simple one: Here on Earth, the presence of water has been key to the evolution of Earthlings, things like you and me and every other living thing on the planet. A history of water on Mars might have led to the rise of Martians, even simple ones like all the bacteria teeming in this pool and in the very rocks themselves."

Michael Mackay: "Has there been water on Mars, is there water on Mars today? Was Mars perhaps like the Earth many millions of years ago when all of sudden lost its atmosphere, lost its water? And the most important question that we've been asking ourselves for many, many years, is there life on Mars?"

Narration: After a seven month crossing, the first ship in the flotilla, Europe's Mars Express, was closing on the Red Planet at nearly 20,000 kph.

While the ultimate destination was orbit, it carried Beagle 2, a British-built probe designed to land on the surface and search for signs of life.

Michael Mackay: "We were flying directly on a crash course with Mars to target the Beagle Lander."

"It separated and we saw beautiful pictures of the Lander disappearing off in the distance on its course to Mars."

Narration: It would be the last time anyone saw or heard from Beagle again. On Christmas Day 2003, forty five million pounds worth of lander entered the Martian atmosphere and disappeared without trace.

Mars Express without Beagle Now, Mars Express would follow right behind if they didn't shift it into orbit...

Michael Mackay: "If we missed that capture at Mars, we had lost this mission all together."

"We went around the back with no signal, we didn't know what was happening."

"We picked up the first signal and I saw it on the screen, and that was an enormous relief."

Narration: Now safely in orbit, Mars Express began its detailed interrogation of the planet below...

David Southwood:"The disappointment of Beagle was of course very great at the time but we just knew Mars Express was going to make a unique contribution to Martian history."

Narration: On the other side of the Atlantic, NASA was preparing for the imminent arrival of their Mars Exploration Rovers.

Previous American Mars missions had revealed a frozen, sterile planet.

But with every passing visit, more features were spotted that suggested water had once flowed over its now desolate surface.

Even many impact craters show signs of having once been flooded.

To prove it, NASA wanted to land a rover in one. They chose Gusev Crater...

Matt Golombeck: "It's a hundred fifty or sixty kilometre diameter crater that has an incredibly smooth flat floor and it looks like this was a crater lake at some time in the past."

Dr Steve Sqyres: "The journey that Spirit has made has been pretty remarkable. We landed on what we thought, expected, still believe, was once a dry lakebed?" "Umm, but when we first looked around what we saw was lots of lava, basalt."

"So we scratch our heads and say okay, what will we do? Okay, all we got here is lava."

Narration: They soon had a far more serious dilemma on their hands: Spirit drove off the lander, across to its first main rock target, and then promptly stopped communicating...

"After every beep, and those are what we'd send, you just got to tell us you heard it. And to go through those periods and just... nothing."

"I'm not hearing anything

"We had completely lost control of the vehicle"

"We've got partial control of the vehicle!"

Narration: Spirit was close to death when the problem was found: a memory fault causing it to constantly restart itself.

Womans Voice: "He sees it, sees it"

Narration: NASA regained control of the rover with its battery power dangerously low and only hours before the Opportunity rover was due to land.

Opportunity, had been sent to an altogether different target: the smooth sands of Meridiani Planum ...

Matt Golombeck: "We saw a mineral signature from orbit of a coarse grained grey haematite and that is a mineral on Earth that typically forms in liquid water, and so it's the only place on the whole planet, pretty much, that is bouncing with this signal; it says 'this is coarse grained haematite found here, usually forms in water, land here.' So we said 'what the heck!'"

Narration:Opportunity then fluked the luckiest landing in the history of space exploration. Landing site details ex MGS It bounced across the sand and rolled to a stop at the bottom of a small crater, seen here from orbit...

They called it Eagle Crater - the ultimate hole in one...

Dr Steve Sqyres: "It had a layer of bedrock exposed. It was literally about this thick, it was 40 centimetres of rock, okay. And that was where we found all the most exciting stuff."

"It was where we found the evidence for water that had evaporated away and left salts behind. It was where we found the little blueberries, the little spherical things. It was where we found the little wave ripples. I mean all of that was there."

Matt Golombeck: "What we found was exactly what we had hoped; this coarse grained haematite is in the blueberries, as we call them, and they are concretions that formed in significant bodies of water. And you know, it's the most significant find ever, from a landed mission, no question."

Narration: Opportunity had already completed NASA's main mission objective - it had found proof of past, liquid water on Mars.

Dr Steve Sqyres: "Everything that we're seeing is fully consistent with shallow water. Now up to my knees, up to my neck, 100 feet deep, I dunno."

Narration: Opportunity was sent to find the rest of the story. It arrived at a second, much deeper crater...

Dr Steve Sqyres: "The beauty of Endurance Crater is that it excavates down through like 20 metres of layered rocks. And by going down into it moving deeper down into older rocks we can travel into the past on Mars."

Narration: Climbing into the crater was tempting but risky.

Back on earth, engineers mocked up a copy of the crater wall with flagstones from the local hardware store. It was so steep the humans needed ropes, but the rover could climb it...

Dr Steve Sqyres: "As far as we have been able to go down this stack it's all salty. And so there was more water here involved than we would have initially guessed."

Matt Golombeck: "From where we landed at Eagle Crater all the way over to Endurance. The layers look just about the same, so that tells you that the sea or ocean or pond was in fact a pretty big pond, and is probably bordering on a small sea at least and it could have been part of a global ocean."

Narration: A clearer portrait of ancient Mars was beginning to emerge.

Everything seemed to confirm what scientists had long suspected - Mars and Earth was once very similar planets...

The stereo camera on Mars Express was now busy snapping extraordinary images of the titanic chasms in the Valles Marineres, a massive canyon system over 7 kilometres deep...

Michael Mackay: "This is what we're actually seeing its not science fiction anymore its is real fact and real landscapes from another planet."

"You can imagine billions and billions of gallons of water which should rush down and carved a canyon through this."

"And I think the questions it poses where did all this water come from if it was water where did it go?"

Narration: If you follow the natural lie-of-the-land on Mars, it is obvious that water would have pooled in an enormous low-lying basin covering the northern third of the planet. The landscape here is very smooth, suggesting it has been partially protected from meteor impacts or buried in sediment.

The clues all point to Mars being an established water planet at the same time life was just getting started in the oceans on Earth.

Richard Smith, reporter: "It seems almost certain now that once you could have walked upon a Martian shoreline and gazed out upon a Martian sea. And for all the world it would have looked like home. And that makes the whole question of life on Mars much more interesting."

Narration: Opportunity it seems was beach combing along a 3.7 billion year old shoreline...

Dr Steve Sqyres: 'This is the kind of place that would have been suitable for life. Now that doesn't mean life was there. We don't know that. But this was a habitable place on Mars at one point in time.'

Matt Golombeck: "There are actually suggestions that Mars, being further out, smaller in size, could have been warmer and wetter sooner - actually more habitable - so there's a suggestion in fact life could have actually started on Mars and come to Earth. So we are all Martians, not just me... (laughs)"

Narration: On Earth, the world went about its business, oblivious to the great adventure above. Even for the rover teams, life had slipped into a regular routine, though work in the office was distinctly unusual...

Matt Golombeck: "You get up in the morning and you go to Mars. And you learn something new everyday. I don't know how what more fun there could be."

Mark Adler: "It just amazes me sometimes when I sit back and say 'Oh, those are pictures from Mars. We are actually operating this vehicle 200 million miles away and it's doing these amazing things and telling us things about Mars that people didn't know about Mars before. Truly rewriting the history books on Mars."

Narration: Back at Gusev Crater, Spirit was still having a tougher time of it. Now fully recovered, the rover had battled for 3 months across a sea of basalt boulders to the distant Columbia Hills, in the hope of finding its own water story...

Mark Adler: "As soon as we got the edge of the hills, in fact the instant we got to the edge of the hills, we looked down and boom, there's these rocks like nothing we had ever seen before."

Narration: One of these was Pot o'gold, a knobbly thing glued together with hardened veins of haematite, deposited when water flowed through cracks in the ground.

All the interesting rocks here had rolled down the hill from outcrops above.

Spirit began to climb...

Never before had mountaineering been attempted on another planet...

Larry Soderblum:"We like to cross this patch we'd like to go cross that greenish patch there. Basically that's a bit of a ridge facing to the south..."

Narration: ...and no climber before has needed to keep solar panels turned to the sun.

To add to the challenge Spirit had a problem with its right front wheel and was now climbing uphill backwards.

Richard Smith, reporter: "So how difficult is this going to be to climb up here with a dodgy front wheel?"

Larry Soderblum: "Well here's the deal - if we turn on a slope map - anything which is cyan or turquoise or blue is off limits."

Richard Smith, reporter: "Too steep?"

Larry Soderblum: "Too steep to get up."

Narration: By now, Spirit had travelled six times further than designed.

Dr Steve Sqyres: "Spirit was always the difficult child before we launched them. Once we got there though it changed dramatically.

"To see poor little delicate Opportunity trying to struggle her way across the Gusev plains for 3 kilometres I frankly don't know if she could have made it, I really don't."

Narration: Sixty metres up, a patch of bright soil churned up by the rover attracted the scientists' attention: it was 50% salt.

Gusev Crater must indeed have once been a massive crater lake. But if anything once lived here, it - like the water - is long gone. Or is it? Or so we thought...

The surface of Mars today is freezing cold, dry as a bone and blasted by cosmic rays.

But the view from orbit is telling a revolutionary story of water surviving to this day on Mars. ...

Extensive deposits of water ice have now been proven to lurk below the dust and dry ice at both the North and South poles.

But it's the extent of frozen water in the ground, which is extraordinary. Blue regions here indicate where NASA has detected water in the soil - extending in patches all the way to the equator.

Astonishingly, Mars Express has even photographed what seems to be ancient pack ice buried under dust near the equator. It looks as if this was a sea that formed and froze over when underground water gushed to the surface only 5 million years ago.

Elsewhere, remnant glaciers point to a Martian Ice Age and an active water cycle as recently as the last few million years...

David Southwood: "I've got to tell you, ten years ago I don't think any of us expected to be where we are now in our feelings about Mars." "This is the year of Mars showing water in various forms and for me Mars is a much more alive place. It's a planet that is doing things."

Narration: Liquid water might be springing to the surface right now from the walls of craters and the flanks of volcanoes, which are also proving to be not all extinct as once thought.

Clearly, Mars remains geologically active.

Vittorio Formisano thinks it may be biologically alive as well ...

Last year his spectrometer on Mars Express detected methane, a gas released on Earth by both volcanoes and methanogenic bacteria - and then he found a second gas formaldehyde...

Vittorio Formisano: "I see at the moment no other explanation than life - methanogenic bacteria being present on Mars producing huge quantity of methane and oxidised methane into formaldehyde. That's what we see in the atmosphere."

Narration: If Formisano is right then living unseen in the Martian underworld today are vast populations of micro-organisms. As they release methane, it drifts upwards towards the surface, with most of it being converted into formaldehyde as it reacts with damp and rusty Martian soil.

Because formaldehyde survives only about 7 hours in the Martian atmosphere, Formisano is convinced the methane must be being produced daily...

David Southwood: "Of course one has to be very critical of whether he's really got his understanding of the instrument right. And for me, I've known Vittorio for many years and I think he's a very careful guy. So for me my prejudice was already on his side."

Narration: These ground-breaking discoveries were the hot topics of a recent ESA science meeting in the Netherlands.

Formisano's methane is linked to concentrations of water vapour around the equator, including the region of the frozen sea, formed it seems by an eruption of underground water...

John Murray: "Because it's come out of the ground in this one rush the implications are that there are wet warm spaces beneath the surface of Mars. I'm not saying that life has developed but if it is going to be anywhere on Mars it will be in these warm wet spaces just below the surface and therefore we might find traces of life in this frozen sea."

Narration: Any day now, Mars Express will deploy its ground penetrating radar, and the hunt will begin in earnest for the suspected underground reservoirs of liquid water, warmed by the heat of the planet.

As for the rovers, they have now survived nearly 6 times longer than originally planned and their mission has been extended to 2006.

They've been given a boost by the Martian wind clearing their dusty solar panels, but there will inevitably be dark days ahead.

Matt Golombeck: "This is like a thirty year old VW bug, you know. There's no warranty on these things anymore. So you do what you can and eventually something is going to break and then you'll weep into your beer that they are not there any more."

"What will it be like to say goodbye to these creatures?"

Dr Steve Sqyres: "It'll be hard, you know. I mean we've poured so much of ourselves into these things for so many years now, it'll be very sad to see them go. You know if the Rovers had died early in the mission before they'd accomplished all that they've accomplished that would have been devastating. To lose them after they've led such rich and full lives, you know I'm not going to feel like celebrating. I'm going to be sad."

Narration: In their first year at Mars, all three missions have far exceeded expectations. Their messages home over the last year have changed forever our view of Mars ...

Michael Mackay: "I think the knowledge of Mars will come into a new era with a contribution of Mars Express and the NASA Rovers that will take us into a new understanding of the planet that is our neighbour."

Vittorio Formisano: "Two years ago the question was: 'Had life been present in Mars in the past?' The question today is: 'Is life present today on Mars?' And this is a major change."

Dr Steve Sqyres: "Mars is an incredibly complex planet and we're seeing little bits and pieces of the story. But you know if someone asks you, well describe to me what the Earth has been like. You know, it's a complicated place and Mars is complicated too."